1. Field of the Invention
This invention relates generally to an apparatus for measuring the impurity or dopant concentration in a semiconductor body and more particularly to an apparatus and technique for measuring the surface potential and impurity concentration in the depleted region created under a biased, insulated, electrode placed over the body.
2. Description of the Prior Art
U.S. Pat. No. 3,840,809, assigned to the same assignee as the present invention, is directed towards an apparatus and method for measuring the properties of dielectric materials by measuring simultaneously the amount of charge injected into the dielectric and the voltage required to restore the surface potential to its original state.
U.S. Pat. No. 3,995,216, assigned to the same assignee as the present invention, describes an apparatus and method of measuring the surface state charges in a metal insulator semiconductor structure by measuring simultaneously and directly the amount of charge injected into the insulator, the net change in the semiconductor body and its surface and the change in surface potential of the semiconductor body.
U.S. Pat. No. 3,668,523 teaches the testing of the properties of dielectric layers which exhibit a voltage dependent capacitance.
IBM Technical Disclosure Bulletin, Vol. 19, #8, January 1977, on pages 3091 and 3092, describes a technique for measuring doping concentration of a semiconductor.
IBM Technical Disclosure Bulletin, Vol. 19, #12, May 1976, on pages 4226-4228, teaches that the impurity concentration of a semiconductor can be inspected.
None of the above prior art references however teach or disclose that under non-equilibrium conditions, the surface potential and impurity or doping concentration in the semiconductor body can be rapidly and directly measured.